Abstract: In this study, we examined the effect of hot air drying at three different temperatures on the physical and chemical properties of waxy corn (cv. ‘CaiTianNuo 6’). A near infrared grain analyzer and low-field nuclear magnetic resonance were respectively used to analyze changes in the moisture content and migration, and scanning electron microscopy, differential scanning calorimetry and a rapid viscosity analyzer were used to determine concomitant changes in the microstructure, thermal properties and processing characteristics of waxy corn. The results showed that waxy corn had a significant change in T21 and A21 during hot air drying, and T21 was reduced from 1.97 ms to 1.37 ms as the moisture content decreased from 29% to 13% during hot air drying at 30 ℃. Due to water loss, the state of bound water was converted from loose to tight binding to macromolecules. As drying proceeded at 70 ℃, the viscosity characteristics changed significantly (P < 0.05). The peak viscosity of corn starch paste increased firstly and decreased later. Additionally, the gel hardness, adhesiveness, chewiness and resilience of the starch gel progressively decreased (P < 0.05). During hot air drying, the thermal characteristics of waxy corn starch changed, and the gelatinization temperature gradually increased.

Key words: waxy corn, water state, microstructure, processing characteristics